The present invention relates to a U-joint construction for joining a drive shaft and a driven shaft.
In appliances as well as in other applications, it is sometimes necessary to couple a drive shaft to a driven shaft by means of a flexible coupling that permits relative misalignment between the drive shaft and the driven shaft. One prior art shaft coupling is shown in U.S. Pat. No. 5,267,903 and includes a drive coupling and a driven coupling which are attached to the drive shaft and the driven shaft. Between these two couplings is an intermediate coupling which engages the two couplings and transfers rotational movement therebetween. The intermediate coupling includes on one face a pair of spaced apart channels and on the opposite face a pair of spaced apart channels which run in a direction orthogonal or transverse to the ones on the opposite side of the intermediate coupling member. Each of the drive coupling and driven coupling include teeth which also engage in the channels on the opposite sides of the intermediate coupling member.
The intermediate coupling member permits the drive coupling and the driven coupling to move longitudinally in the spaced apart channels thereof. However, the teeth from the drive coupling and the driven coupling are square and fit the square shaped configurations of the channels so that there is a minimal ability or no ability to rotate the teeth within the channels. Thus the coupling member shown in U.S. Pat. No. 5,267,903 permits sliding movement within the channels, but does not permit any rotational movement within the channels.
Therefore, a primary object of the present invention is the provision of an improved U-joint construction for joining a drive shaft to a driven shaft.
A further object of the present invention is the provision of a U-joint construction which includes an intermediate coupling member having channels in its opposite sides, and which permits both longitudinal movement of the drive coupling and driven coupling within those channels as well as pivotal movement of the drive coupling and driven coupling within those channels.
A further object of the present invention is the provision of an improved U-joint construction which permits both the drive coupling and the driven coupling to pivot relative to the intermediate coupling about a vertical axis and a horizontal axis and to slide longitudinal with respect to the channels in the intermediate member.
A further object of the present invention is the provision of an improved U-joint construction which transfers a constant rotational velocity from the drive shaft to the driven shaft throughout misalignment of the drive shaft to the driven shaft.
A further object of the present invention is the provision of an improved U-joint construction which does not require lubricating.
A further object of the present invention is the provision of an improved U-join construction which is economical to manufacture and durable in use.
The foregoing objects may be achieved coupling for joining a drive shaft and a driven shaft. The shaft coupling includes a drive coupling member attached to the drive shaft and having a drive bearing extending therefrom. A driven coupling member is attached to the driven shaft and has a driven bearing member extending therefrom. An intermediate coupling member capable of rotating about an intermediate rotational axis is positioned between the drive coupling member and the driven coupling member. A first channel on the intermediate coupling member includes a longitudinal first channel axis and extends transversely to the intermediate rotational axis of the intermediate coupling member. A second channel on the intermediate coupling member has a longitudinal second channel axis extending transversely to the intermediate rotational axis and also extending transversely to the first channel axis of the first channel.
The first and second channels each have a squared U-shaped cross section with the open U-end facing towards the drive bearing and the driven bearing respectively. The drive bearing protrudes within the first channel and engages the intermediate coupling member for rotating the intermediate coupling member about its intermediate rotational axis. The driven bearing member protrudes within the second channel and is engaged by the intermediate coupling member for transferring rotational movement from the intermediate coupling member to the driven shaft. The drive bearing is capable of pivoting within the first channel about a first pivotal axis extending in the same direction as the first channel axis and about a second pivotal axis transverse to the first channel axis. The driven bearing is capable of rotation within the second channel about a third pivotal axis extending in the same direction as the second channel axis and about a fourth pivotal axis transverse to the second channel axis.
According to another feature of the invention the shaft coupling includes a drive bearing having a rounded surface protruding within the squared U-shaped first channel and the driven bearing includes a rounded surface protruding within the squared U-shaped second channel. The drive and driven bearings are longitudinally movable within the first and second channels respectively along the first and second channel axes respectively.
According to another feature of the present invention the drive and driven bearings each have an elongated drive bearing axis and an elongated driven bearing axis respectively. The rounded surfaces of the drive and driven bearings are concentric to the drive bearing axis and the driven bearing axis respectively.
According to another feature of the present invention the U-shaped first and second channels each include a channel floor and opposite channel side walls. The drive bearing and driven bearing are movable away from the channel floors of the first and second channels respectively to permit the pivotal movement of the drive and driven bearings about the second and fourth pivotal axis respectively.